if she only has $15 to spend we will use the ≤ sign as this will make sure we either spend less or exactly $15. We will assign x to number of snacks and y to number of magazines, so our magazines will be 1.25y and snacks are 1.15x. since we hav two different variables, we need a second equation, if we will get equal of either, that means x=y so now we have
[tex] \left \{ {{x=y} \atop {1.25y+1.15x \leq 15}} \right. [/tex]
since x=y, we can replace either x or y in our second equation
[tex]1.25y+1.15y \leq 15[/tex]
solve:
[tex]1.25y+1.15y \leq 15[/tex]
[tex]2.40y \leq 15[/tex]
[tex]y=6.25[/tex]
since we cant have .25 of either one, we will say y is 6 and since x=y, that means x is 6 too
